Circle And System Of Circles Question 20
Question: If the line $ 3x-4y=\lambda $ touches the circle $ x^{2}+y^{2}-4x-8y-5=0 $ , then $ \lambda $ is equal to
[Roorkee 1972; Kurukshetra CEE 1996]
Options:
A) - 35, -15
B) - 35, 15
C) 35, 15
D) 35, -15
Show Answer
Answer:
Correct Answer: B
Solution:
Accordingly, $ \frac{3(2)-4(4)-\lambda }{\sqrt{3^{2}+4^{2}}}=\pm \sqrt{2^{2}+4^{2}+5} $
$ \Rightarrow -10-\lambda =\pm 25\Rightarrow \lambda =-35,\ 15 $ .
BETA
